The Mil Design Bureau, led by Mikhail Leonteyevich Mil, was one of the leading Soviet plants promoting combination of helicopters and firepower. Mil was personally involved in the development of a prewar A-7 autogyro equipped with a machine gun for its own defense and two more for destroying ground targets. However, this type did not reach mass production. But Mil continued thinking about arming the rotorcraft, especially during his practice design of several Bratukhin helicopters, of which some models were intended for artillery spotting and clearly showed that helicopters could play an important role in the army and could be a part of front line units. When the Mi-1 helicopter was test flown for the first time on 20th of September 1948, it was clear that a very versatile type was born. It became the first mass produced Soviet helicopter with a wide variety of special variants for both civil and military applications. It had just entered the regular service with the Soviet Army, when US forces began using their Bell OH-13s for attack missions in Korean War.